The Sunbeam Longstroke was the fastest production, single cylinder, side-valve motorcycle in its day.The model stayed in production for the life of the company and the subsequent AMC take-over in late 1937.The Model 6 492cc side valve single had benefitted from the company’s experience with a prototype machine raced at the 1921 French Grand Prix.
Dubbed the “Longstroke” by enthusiasts and the factory alike as a means of differentiating it from the existing 85mm x 88mm engine, whose origins lay in the design dating from 1913, the new power plant had dimensions of 77mm x 105mm giving a displacement of 492cc.
The new model quickly demonstrated its worth, securing victory in the 1922 Senior TT with a lap of 59.99 mph in the hands of Alec Bennett resulting in the model being marketed as the “Longstroke TT” for the 1922 and 1923 seasons.
This fine “Longstroke“ combination is equipped with a complete Bosch lightning system, AMAC carburetor. The bike bears it´s first paint has a wonderful patina. It runs well.